1. Field of the Invention
The present disclosure relates to a vehicle lamp configured to irradiate infrared light in a vehicle forward direction.
2. Related Art
In recent years, an infrared-light night vision camera system is used in order to improve night driving safety. The infrared-light night vision camera system picks up an image in a vehicle forward direction while irradiating infrared light in a vehicle forward direction and recognizes a state in a vehicle forward direction by displaying the pick-up image on a monitor or the like.
In terms of the infrared-light night vision camera system, it is possible to obtain information in a vehicle forward direction, the information being not obtainable during a general visible light irradiation operation. For example, in a state where a head lamp unit irradiates the visible light in a low beam mode, it is not possible to obtain information on a space above a cutoff line of a low beam distribution pattern. However, when the infrared light is irradiated together with the visible light, it is possible to sufficiently recognize a situation in a vehicle forward direction without giving a glare to a driver or the like in the opposite vehicle.
In the infrared-light night vision camera system, the infrared light in a near-infrared range is used. However, since a red light is included in a part of the irradiated light, a front lens is tinged with red when a vehicle lamp is observed from the front side upon irradiating the infrared light, thereby causing a problem in that the driver in the opposite vehicle feels uncomfortable.
For this reason, in the past, as disclosed in JP-A-2003-19919 or JP-A-2004-146162, a study has been carried out which prevents in advance the front lens from being tinged with red in such a manner that the red light and the visible light are simultaneously irradiated from the vehicle lamp.
In the vehicle lamp disclosed in JP-A-2003-19919, the red light and the visible light are simultaneously irradiated in such a manner that an infrared light non-formation region, through which a visible light component of a light source passes, is formed in the outer periphery of an infrared light transmission film through which a red light component of the light source passes.
On the other hand, in the vehicle lamp disclosed in JP-A-2004-146162, the red light and the visible light are simultaneously irradiated in such a manner that an incandescent bulb is disposed in front of an infrared light transmission filter disposed in a lamp room and the incandescent bulb is simultaneously turned on upon irradiating the red light.
The vehicle lamp disclosed in JP-A-2003-19919 or JP-A-2004-146162 has a function of preventing the front lens from being tinged with red upon irradiating the infrared light in a vehicle forward direction, but does not have any other functions.
That is, the vehicle lamp disclosed JP-A-2003-19919 is not configured to irradiate the visible light.
On the other hand, the vehicle lamp disclosed in JP-A-2004-146162 is configured to irradiate the visible light by turning on the incandescent bulb in addition to the infrared light. However, since the light of the incandescent bulb is not controlled upon being emitted from the front lens, it is difficult to form a desired light distribution pattern by means of the light of the incandescent bulb.